Glass compositions for ultrasonic delayed action lines

ABSTRACT

Glass compositions for ultrasonic delayed action lines characterized by low temperature coefficient of the ultrasonic travel time and by low internal attenuation of sound waves and transformation temperatures of between 550* and 620* having the following composition: SiO2 54.4 - 59.8 wt-% B2O3 0 - 3 wt-% K2O 7.3 - 13.0 wt-% BaO 12.0 - 19.3 wt-% ZnO 6.7 - 8.7 wt-% PbO 0-15.7 TiO2 0-2 Al2O3 0-3 Sb2O3 0-2 As2O3 0-2 WO3 0-3

United States Patent [191 Faulstich et al.

GLASS COMPOSITIONS FOR ULTRASONIC DELAYED ACTION LINES Inventors: Marga Faulstich; Norbert Neuroth, both of Mainz, Germany Assignee: Jenaer Glaswerk Schott & Genn,

Mainz, Germany Filed: Aug. 26, 1971 Appl. No.: 175,340

Related US. Application Data Continuation-impart of Ser. No; 804,595, March 5, 1969, abandoned.

Foreign Application Priority Data Mar. 8, 1968 Germany ..P 16 96 064.8

US. Cl. ..l06/53, 106/52, 106/54 Int. Cl. ..C03C 3/10, C036 3/04, H03h 7/30 Field ofSearch 106/52,53,54; 333/30 [111 3,723,143 1 Mar. 27, 1973 Primary Examiner-Helen M. McCarthy Assistant Examiner-M. Bell Attorney-Ralph D. Dinklage et al.

[57] ABSTRACT Glass compositions for ultrasonic delayed action lines characterized by low temperature coefficient of the ultrasonic travel time and by low internal attenuation of sound waves and transformation temperatures of between 550 and 620 having the following composition:

5 Claims, 1 Drawing Figure PATErmnmzm 3,723,143

INVENTOR. MAKGA FAZ/LST/Cf/ NORBEKT NEUFOTH A T'TORNEYS GLASS COMPOSITIONS FOR ULTRASONIC DELAYED ACTION LINES This application is a continuation in part of application Ser. No. 804,595, now abandoned.

The present invention relates to glass compositions suitable for ultrasonicdelayed'action lines, and in particular to compositions of glasscharacterized by low ultrasonic speed temperature coefficients.

1t isknown in the art that certain types of glass compositions can be used for ultrasonic delayed action lines. The most important requirement of such glasses is that inthese glasses in which the velocity of sound. changes with temperature in such a way that the propagation time 2 of the sound is constant in the temperature rangeof about to 50C that the relative change amounts to (l/z) (dz/dT)s1.5 10-/C. In. addition, the following are also desirable properties of such glass compositions: short soundpaths, i.e., low sound velocity, low mechanical attenuation of sounds, small after-effects, low densities, suitability for the application thereto of solderable metal coatings and good chemical stability.

In view of the fact that in the method of preparing the glasses for application of the solderable metal coatings the burning in with solutions of various metals has gained wide acceptance and that in this procedure, the glass must be heated to 500C and above, it is ex tremely advantageous and in fact necessary that the glasses have transformation temperatures about 500C.

A number of different glasses including the following have already become known which exhibit a low temperature coefficient of the time of propagation of ultrasonic waves:

a. glasses having a high-lead content. These are characterized by a low attenuation (value of the logarithmic decrement 0.5 X 10-") and a relatively low transverse velocity of sound amounting to 2500-2600 m/sec. The transformation temperatures of such glass types are, however, in the range of 470 480C and are thus too low to prove satisfactory for the burning in required connection with the application of metal to the glass coatings. In addition, the elevated density of these glasses 8 3.6) constitutes a disadvantage in view of the fact that the weight of the delayed action line should be as small as possible.

7 b. glass containing no lead or a low percentage of lead and having a titanium content in excess of 2.0 wt

percent. These glasses exhibit a higher velocity of sound and a greater innerattenuation. Even though this may be of interest, particularly in those instances in which transformers having a high efficiency and a solder layer characterized by low losses can be used as a result of the higher attenuation (values of the logarithmic decrement 1.0to 2.5 X 10- interfering signals in the glass body are suppressed by undesired reflections. However, these glasses have transformation temperatures amounting to 500 540C so that they can be employed more advantageously for a burning in metalization.

It is accordingly an object of the invention to provide a new field of glass compositions of the character described.

It is another object of the invention to provide improved ultrasonic'delayed action line glass compositions.

A further object is to provide new glasses meeting the above objects and being characterized by low internal deadening or muffling of sound waves and transformation temperatures of between 550 and 620C.

Other objects and various further features of novelty and invention will be pointed out or will occur to those skilled in the art from a reading of the following specification.

In accordance with the invention it has now been found that glasses having the compositions as hereinafter set out can be used most advantageously for ultrasonic delayed action lines:

$101 54.4 59.8 WI-% 8203 0 3 Wt-% K20 7.3 13.0 W1-% B 12- 15.7 W1'.-% ZnO 6.7 9.7 wt-% PbO O- 15.7 WI-% The glasses of the invention have a low temperature coefficient of the time of propagation of ultrasonic waves with frequencies in the megacycle range. They are characterized by a low internal attenuation (values of the logarithmic decrement ofO.5 to 1.0 X 10') and a relatively low velocity of. sound and, at the same time, their transformation temperature lies between 500 and 620C. In addition, the density of such glasses is lower than that of the glasses having a high lead-oxide content.

In accordance with one feature of the invention, it is possible, by including in the glass compositions, small amounts of B 0 3 percent by weight), to shift the temperature minimum of the change in the time of propagation to a desired temperature without substantially altering the internal attenuation. It is also possible to replace in the known manner a part of the K 0 by the corresponding molar amounts of Li Oor Na O; this interchange should however be avoided to prevent impairing the thermal aftereffect.

For the purpose of crystallization stabilization there may be introduce 0 3 percent by weight A1 0 0 2 percent by weight Sb O 0 2 percent by weight As O and/or 0 3 percent by weight W0 For the purpose of increasing the chemical stability, it is possible to introduce 0-2 percent by weight TiO In the following table there are set out illustrative glasses according to the invention, the same are not, however, to, be construed as limiting the scope of the invention.

T A B L E l OXIDES 1 2 3 4 SiO, 59.8 57.6 54.9 54.4 8,0, 3.0 K,0 11.0 13.0 7.3 8.4 BaO 19.3 12.0 13.8 13.6 ZnO 6.7 8.0 8.7 7.6 PbO 7.1 14.3 15.7 TiO, 2.0 0.5 As,0, 0.2 0.3 0.5 0.3 log. decrement 10 0.7 0.8 0.6 0.5 "trans 3093 2934. 2880 2838 (m/sec) Transformation Temperature (C) 612 579 584 563 Specific Gravity (Kle 2.85 2.91 2.13 3.15 [1/2 (dz/dT)]10'/C (10-50C) 1.2 1.0 1.5 0.9

By using piezoceramic transformers, of lead zirconate-titanate, delay lines having a delay time of 64 microseconds were prepared from the glasses 1 to 4 of Table I. in the drawing attached hereto the influence of the temperature on the delay time expresses as A z in nanoseconds is set out.

The glass compositions according to the invention can be prepared for instance, as follows:

A mixture comprising the following components is prepared.

Oxides Wt. Raw Materials Wt-portion 100 liters SiO, 54.4 SiO, 196.232 kg K,O 5.0 I(,CO 26.510 kg K,O 3.4 KNO, 26.294 kg BaO 13.6 BaCO 63.418 kg ZnO 7.6 ZnO 27.426 kg PbO 15.7 Pmo. 57.854 kg A5 0, 0.2 As,0, 0.721 kg The carefully blended mixture is then placed for about 16 hours (for 100 liters) at 1380 1400C into a crucible made of platinum or into refractory ceramic crucibles or into tank furnaces of refractory ceramic material (continuous glass melting furnaces). The fining time at 1440C amounts to approximately 14 hours. The casting temperature amounts to approximately 1300C. The cooling time may be selected arbitrarily to amount to 7 or 5C per hour.

This type of glass is particularly well suited for manufacture utilizing continuous glass-melting furnaces, known to the skilled in the art. The fusing temperatures required must be adapted to the volume and the desired output rate as needed for blocks or pressed items.

What is claimed:

1. A glass composition adapted for use as ultrasonic delayed action lines having a low internal attenuation, a relative change of the propagation time z of the sound in the temperature range of about 10 to 50C of (Hz) (dz/dt) s 1.5 X 1(/C and a transformation temperature of between 550 and 620C consisting essentially of:

ing:

ing:

ing:

ing:

SiO, 8,0, 14,0 BaO ZnO PbO TiO Al,0, 86,0, As,0, W0;

SiO, 8,0, K,O BaO ZnO As,0

SiO, K 0 BaO ZnO PbO TiO, As,O,

SiO, K,0 BaO ZnO PbO As,0,

SiO, K 0 BaO ZnO PbO TiO, A5 0;

. A glass composition according to claim 1 compris- 59.8 wt 3.0 wt 11.0 wt 19.3 wt 6.7 wt 0.2 wt

. A glass composition according to claim 1 compris- 57.6 wt% 13.0 wt% 12.0 wt% 8.0 wt% 7.1 wt% 2.0 wt% 0.3 wt% A glass composition according to claim 1 compris- 54.4 wt 8.4 wt 13.6 wt 7.6 wt 15.7 wt 0.3 wt

54.9 wt 7.3 wt 13.8 wt 8.7 wt 14.3 wt 0.5 wt 0.5 wt

UNKTEJ STATES PATENT P0-10au (5/59) I v1 rw .1-

CERTIFICATE 03+ (IURRECMON Patent N... 3 bate March 27, 1973.

Inventor($ 1 MA BGA FAULSTICH ET AL It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Front oage,

following should be added;

ZnO

PbO

Col. 1, lihe 43 Col. line 17 I Claim 1, line I 13,;

l Signed and- (SEAL) Attest:

EDWARD DLFLETCHERJR.

Attesting Officer 54,4 59.8 Wt. 7. C! 3 wt. 3 7 5.3 13.0 wt. 7.. 112,.0 19.3 7.

61.7 o 8.7 wt. 7.

.. c 15.7 .wt'. 2. 2 'wt'. 0 i .3 .wt. 5% l 'i Q 2 .wt. 7, v 0 2 wt. 7. v 0 3 wt i let'e in"- before required i r etween "required and "connec'tion".

FY12 5.7 wt. 7," should read 12 19.3 wt-.1,"

' 'Ti should read Tio --I 'ealed this 20th day of November 1973.

I RENE D. TEGTMEXER- v Acting Commissioner of Patents 

2. A glass composition according to claim 1 comprising: SiO2 59.8 wt % B2O3 3.0 wt % K2O 11.0 wt % BaO 19.3 wt % ZnO 6.7 wt % As2O3 0.2 wt %
 3. A glass composition according to claim 1 comprising: SiO2 57.6 wt % K2O 13.0 wt % BaO 12.0 wt % ZnO 8.0 wt % PbO 7.1 wt % TiO2 2.0 wt % As2O3 0.3 wt %
 4. A glass composition according to claim 1 comprising: SiO2 54.4 wt % K2O 8.4 wt % BaO 13.6 wt % ZnO 7.6 wt % PbO 15.7 wt % As2O3 0.3 wt %
 5. A glass composition according to claim 1 comprising: SiO2 54.9 wt % K2O 7.3 wt % BaO 13.8 wt % ZnO 8.7 wt % PbO 14.3 wt % TiO2 0.5 wt % As2O3 0.5 wt % 